The search for effective anti-theft apparatus has been imbued with greater urgency due to the recent surge in what has come to be known as "carjacking" i.e. the forceful commandeering of a vehicle while occupied. In this type of crime, an armed thief approaches a vehicle and demands that the occupants exit and turn over the vehicle, whereupon the thief enters it and drives away. Obviously, the presence of traditional anti-theft mechanisms, namely, those which prevent a vehicle from being started, will only cause the thief to demand that the occupants reveal the hidden switch location, the secret code, or the like. More ominously, such delays are likely to provoke anger and violence on the part of the criminal.
Therefore, there is a need for a system which is activated surreptitiously and which delays the disabling of a vehicle until after the thief has left the vicinity of the crime--thus placing the occupants out of harm's way.
Prior developments in this field may be generally illustrated by reference to the following information disclosure statement:
______________________________________ Pat. No. Patentee Issue Date ______________________________________ 4,940,964 V. Dao Jul. 10, 1990 3,943,376 D. Long Mar. 09, 1976 5,006,843 W. Hauer Apr. 09. 1991 4,682,062 Z. Weinberger Jul. 21, 1987 4,852,680 T. Brown et al. Aug. 01, 1989 5,179,868 R. Thibeault Jan. 19, 1993 4,762,198 L. Vagnone et al. Aug. 09, 1988 4,891,478 P. Gold et al. Jan. 02, 1990 ______________________________________
Electronic circuits for detecting the seatbelt state (i.e. whether it is fastened or unfastened) have been used to sound alarms while in the unfastened-seatbelt state and even to prevent vehicles from being started. See, for example, U.S. Pat. No. 3,943,376. Heretofore, however, it has not been proposed to use a seatbelt to secretly activate a time-delayed anti-theft system.
U.S. Pat. No. 4,940,964 teaches a remote keypad which communicates with an anti-theft system by radio frequency signals. U.S. Pat. Nos. 5,006,843, 4,682,062 and 4,852,680 teach keypads used to control locking systems within vehicles. The rest of the patents are representative of what is in the art.